Quantum Anomalous Hall Effects in Graphene from Proximity-Induced Uniform and Staggered Spin-Orbit and Exchange Coupling

Abstract

We investigate an effective model of proximity modified graphene (or symmetrylike materials) with broken time-reversal symmetry. We predict the appearance of quantum anomalous Hall phases by computing bulk band gap and Chern numbers for benchmark combinations of system parameters. Allowing for staggered exchange field enables quantum anomalous Hall effect in flat graphene with Chern number $C=1$. We explicitly show edge states in zigzag and armchair nanoribbons and explore their localization behavior. Remarkably, the combination of staggered intrinsic spin-orbit and uniform exchange coupling gives topologically protected (unlike in time-reversal systems) pseudohelical states, whose spin is opposite in opposite zigzag edges. Rotating the magnetization from out of plane to in plane makes the system trivial, allowing to control topological phase transitions. We also propose, using density functional theory, a material platform---graphene on Ising antiferromagnet MnPSe${}_3$---to realize staggered exchange (pseudospin Zeeman) coupling.

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Cited by in corpus (8)

• Van der Waals heterostructures for spintronics and opto-spintronics
• Twist-angle dependent proximity induced spin-orbit coupling in graphene/topological insulator heterostructures
• Magnetic proximity effect at the interface of two-dimensional materials and magnetic oxide insulators
• Perfect crossed Andreev reflection in the proximitized graphene/superconductor/proximitized graphene junctions
• Topological edge states of a graphene zigzag nanoribbon with spontaneous edge magnetism
• Ultralong 100 ns Spin Relaxation Time in Graphite at Room Temperature
• Proximity-induced diversified magnetic states and electrically-controllable spin polarization in bilayer graphene: Towards layered spintronics
• Valley-Polarized Quantum Anomalous Hall Phase in Bilayer Graphene with Layer-Dependent Proximity Effects